Specific Aims: The goals of the Mechanical Engineering (ME) Core are to support research of Investigators across the Core Center by designing and building commercially unavailable parts, devices and machines, and by maintaining the machinery currently in use. The aim is to keep the research at the cutting edge in each field aided by the services of the machinists in the ME Core, and to promote collaborations among the individual Pi's. Over the last grant period, the ME Core has helped develop an infrastructure for research at Mount Sinai School of Medicine and Brooklyn College that has facilitated collaboration while enhancing individual research. This has generated new funded projects, as well as new collaborations that will expand the scope of the Core. The ME Core will continue to enhance the infrastructure during the next grant period by providing support for new projects and collaborations, as well as by enhancing work in ongoing projects. This will be accomplished in two Specific Aims. Specific Aim 1: Design and Build Commercially Unavailable Parts and Devices to Broaden the Scope of Research and Foster Collaborations: A. Monkey Single Unit and Locomotion Experiments (Yakushin/Raphan/Cohen): 1. Work with the C/EE Core to develop a training system for monkeys walking on a treadmill in the monkey locomotion experiments, so animals will watch a fixed point in space while they receive a water reward. Mount the screen displaying the targets on the linear treadmill. 2. Design and build (with the C/EE Core) new motor-driven micromanipulators that will be used for single unit studies of gravity-dependent gain adaptation in the monkey, and for unit recording in freely-moving monkeys during locomotion studies. 3. Design and build a device for the Cosmos rotator to measure the cervico-ocular reflex (COR) in monkeys, so the monkey's body can be oscillated with the head fixed or the head can be oscillated with the body fixed. 4. Design and build a primate chair for recording muscle sympathetic nerve activity (MSNA) from the peroneal nerve of monkeys in the COSMOS rotator and on the 'linear sled on a rotator'(Linear Sled). B. Mouse Physiological, Neuroanatomic and Molecular Biological Studies (Yakushin/ Holstein/Sealfon/ Margolskee/Max/Bedrich/Cohen/Sclafani/Raphan): 1. Configure the linear sled and rotator for mice. It is currently used for monkeys. Manufacture a new mouse holder that will fit into the mount on the linear sled. 2. Design and build new gimbal devices that will allow centrifugation of mice at varying levels of g at any attitude relative to the axis of rotation and the centripetal linear acceleration. 3. Mount the binocular mouse eye movement system on the device to record eye movements during centrifugation. 4. Manufacture small rotational devices to test mice at Brooklyn College in studies of food aversion following centrifugation in different orientations. C. Human Motion Sickness and Vestibulo-Autonomic Studies (Dai/Cohen/Kaufmann/Raphan/ Straumann): 1. Design and build with the C/EE Core, a new 3-D optokinetic stimulator with new gears and motors for the OVAR enclosure. 2. Develop a new head holder for the OVAR chair so that the head does not move during the rotations. Remount the video cameras that record eye movements. 3. With the C/EE Core, design and build a computer-controlled device to measure the subjective visual vertical while stationary and during OVAR. 4. Mount humidity and temperature controls in the OVAR enclosure and blood pressure, heart rate, and respiratory devices on the OVAR chair. 5. Design and construct a bed for the Circular Treadmill to place subjects on their sides to habituate their vertical aVOR. D. Human Locomotion Studies (Raphan/Cohen/Cho/Smouha/Olanow): 1. Design and build a mechanism for raising the back of the linear treadmill to study walking downhill. 2. Design and build a gimbaled positioning mechanisms for a laser pointer so that head movements can be directed automatically and tested in patients with dystonia. 3. Design and build a harness on a sliding support on the ceiling to study climbing and descending a staircase. Specific Aim 2: Maintain and repair mechanical equipment: Vestibular research is heavily dependent on a wide variety of mechanical and electromechanical devices. In many instances, maintenance by the original manufacturers is not available but safety is essential. Therefore: 1. Regularly inspect, maintain and, if necessary, replace hoses in the hydraulic system that tilt the OVAR chair used in motion sickness studies. Also, regularly maintain motors that run the linear and circular treadmills. 2. Do emergency repair, small modifications, and routine maintenance of commercial machines, since using outside mechanics, is not only costly but generally not possible